Hypodermic syringe



R. K. CUTTER Feb. 27, 1934.

HYPODERMI C SYRINGE Original Filed July 21, 1930 IN V EN TOR.

BY (/W A TT Patented F eb. 27, 1934 UNITED STATES PATENT OFFICE TheCutter Laboratory, Berkeley, Calif., a corporation of CaliforniaContinuation of application Serial No. 469,447,

July 21, 1930. This application August 15, 1932;

Serial No. 628,790

2 Claims.

This application is a continuation of my application Serial No. 469,447,filed July 21, 1930, for Hypodermic syringe.

This invention relates to improvements in the construction of hypodermicsyringes particularly designed for use in connection with the storage,transportation, preservation and application of biological and similarproducts which are stored, transported, preserved or dispensed insyringe containers.

Objects of the present invention are generally to improve and simplifythe construction and operation of devices of the character described; toprovide a syringe charged with the medicine to be injected and which mayfunction as a storage container but not permit leakage of the medicinefrom the front to the rear of the plunger even when subjected tovibration such as occurs during transit; to provide an improved type ofpiston or plunger which will not permit leakage from the front to theback thereof; to provide an improved piston or plunger which will notjam when pushed forward to eject the medicine from the syringe; toprovide a piston or plunger which will permit a greater tolerancebetween the outer surface thereof and the inner surface of the cylinderor barrel in which it is used; to provide a plunger which is adaptedto'be constructed entirely of a resilient material such as rubber or thelike; other objects being apparent from a reading of the appendeddescription taken in connection with the accompanying drawing whichillustrates the invention. In such drawing- Fig. 1 is a centrallongitudinal section through the syringe; and

Fig. 2 is a perspective view of the plunger showing the operating handleattached thereto.

Referring to the drawing in detail and particularly Fig. 1, A indicatesa cylinder or barrel which in this instance is preferably constructed ofglass, although it may be made of any suitable material. The dischargeend of the cylinder is reduced in diameter to form a neck 2 in which isinserted a rubber sealing plug 3 and this is in turn designed to receivea hollow needle 4 through which the serum is discharged.

The opposite end of the cylinder or barrel is open and provided with aflange 5 and this is protected by means of an annular rubber ring 6which functions as a finger grip. Adapted to be inserted in the cylinderor barrel A is a combination plunger and sealing plug generallyindicated at B and for suitable attachment thereto I provide anoperating handle 7. The plunger con- ,sists of a head member 8, one endof which terminates in a shank-like extension 9 which is adapted toreceive the operating handle. The periphery of the head terminates in anannular flange or ring 10 which forms the contact member of the plunger,and the exterior surface 11 of this member forms a snug fit withrelation to the inner surface of the barrel. The head member 8 alsocarries a plug or filler member 12 and there is an annular groove orspace 13 formed between said plug and contact ring 10 to permit freeexpansion and contraction thereof. The annular groove 13 should be ofsubtsantially greater depth than the contacting surface 11, while thewidth of this groove may be sufficient to admit liquid so that apressure will be exerted on the walls thereof when forward movement isimparted to the plunger during discharge of the medicine; while thatpart 10 comprised between the annular groove13 and the exterior surface11 (taken on a cross section) should be of sufficient thickness to makeand maintain a good contact with the inner surface of the barrel inorder to prevent suificient yielding to permit passage of liquid fromahead of the plunger to points therebehind, such thickness beingdetermined-with a consideration of the softness and flexibility andpossibly other characteristics of the material of which the plunger ismade. This part between the annular groove 13 and the outer periphery isso made that it normally tends to have an outer periphery slightlygreater than the inner periphery of the barrel. The projection 14 servesonly to reduce the residual syringe contents to a minimum and is hereshaped to fit the syringe neck as close.- ly as possible- It will, ofcourse, be modified in shape to fit the neck of any syringe and it canbe entirely eliminated, if desired, in which case a depression or wellis formed within the annular contact ring 10.

The plunger as a whole will preferably be constructed of soft rubber ora similar material and in actual operation it will be inserted in theopen end of the barrel after the barrel has been sterilized. The barrelis then filled with serum through the neck and the plug prevents escape,leakage, or contamination of the serum content. Products such asdiphtheria anti-toxin, tetanus anti-toxin, as well as many otherproducts, may be sold and transported in, and served to the patientfrom, syringes comprising my new invention. Some of these products arenecessary for the saving of human life, but it often happens that aphysician will carry necessary products for many miles to the patientonly to find that on arrival a substantial part of the medicine hasleaked beyond the plunger and has become dried and un-usable, and thisis one of the disadvantages, and it is a very great one, which has inpractical use been obviated by my invention. Now, when the syringe is tobe employed, end pressure is applied to the operating handle and theplunger will then be forced inwardly and during such movement willdischarge the serum through the hollow needle. During such inwardmovement pressure is applied to the liquid and, as this enters theannular groove 13 formed between the filler plug 12 and the contact ring10, an outward pressure is exerted on the inner face of the contactring, thus forcing the contact face '11 into snug engagement with theinner surface of the barrel and insuring complete discharge of the serumcontent.

Furthermore, when the plunger is forced inwardly by means of theoperating handle the plunger as a whole tends to slightly compress dueto frictional resistance and this compressing action further assists inmaintaining a snug engagement between the plunger and the barrel.

While the plunger mechanism illustrated in this instance is primarilyintended for antitoxin syringes which are filled with a single chargeand which are discarded after first use, it is obvious that the plungermay be employed in connection with permanent syringes and like devices.In that case the shank or extension 9 may be provided with moldedthreads or the like so that it may be readily connected with a rod orany other plunger operating mechanism of suitable construction.

In actual practice, the annular ring 10 of the plunger is sufficientlyresilient to expand by compression, friction and by the application ofpressure, while due to its resiliency it may be contracted or forcedinwardly when inserted into a barrel, while said part 10 is suilicientlystrong to maintain a position against the inner surface of the barrelwhich will prevent rearward movement of the medicine therepast. Aplunger thus constructed permits a greater tolerance between the plungerand the inner surface of the barrel than is usually possible withordinary plungers. plunger structure, accordingly, has severaladvantages, towit, it will function both as a plunger and as a sealingplug. Due to the tolerance permitted, it will fit a greater number ofcylinders of varying size with less tendency to leakage or sticking. Itis contractable and it is also automatically expansible when pressure orfriction is applied and, as it is constructed of rubber, it may bemolded or otherwise formed. It will be observed that no matter where across section is taken on the head of my novel plunger, it will comprisespace free from plunger material.

I prefer that the groove 13v have a depth which is substantially twicethe length of the contact surface 11 with the inner wall of the barreland that the sealing plug and plunger B be made entirely of softflexible rubber, but these specific features are not necessarilylimitations of my invention. It is to be noted that 'it is not essentialnor even very important that the pressure exerted by the liquid onmoving the plunger forward in the syringe should be the cause of contactbetween the surface 11 of the plunger head and the inside surface of thebarrel; but what is from the syringe and to exert sufficient force Theagainst the inside wall of the barrel to prevent leakage while the fluidin the syringe is being expelled therefrom or during jarring intransportation, and such thickness and strength will, of course, bedependent upon the resilience and other physical characteristics of thematerial of which the plunger'is made which is preferably rubber. Thisis important since a jar which might exert no pressure on the fluid, saya jar from the side, and which consequently would have little or noeffect on keeping the annular contact surface 11 against the inside wallof the barrel, would tend to have quite the opposite effect, namely, tomake a break or opening so that fluid could leak from the front to theback of the plunger.

While certain features of the present invention are more or lessspecifically described, I wish is understood that various changes may beresorted to within the scope of the appended claims; similarly, that thematerials and finishes of the several parts employed may be such as themanufacturer may decide or varying conditions or uses may demand.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. A combined container and syringe comprising a barrel and a soft,flexible, resilient, elastic member therewithin, said member having arearward portion the periphery of which is substantially smaller thanthe inner periphery of said barrel to form a manipulating shank adaptedto accommodate a manipulating handle, an annular outwardly flaringportion on the forward end of said shank having an outer peripherysubstantially smaller than the inner face of said barrel except wheresaid portion engages therewith and an integral annular contact portionon the forward end of said flaring portion and extending forwardlytherefrom, the outer periphery of said contact portion being normallyslightly larger than the inner face of said barrel, both said annularportions being throughout of substantial thickness sufiicient tomaintain a continuous contact between said contact portion and saidbarrel during shipment and storage and also to prevent curling back tomaintain a continuous ring of contact between said contact portion andsaid barrel on pushing said member forwardly.

2. A combined container and syringe comprising a barrel and a soft,flexible, resilient, elastic member therewithin, said member having aforward portion, a rearward portion and an intermediate portionconnecting said two first mentioned portions, the forward face of saidforward portion having an annular groove therein extending through saidforward portion and at least into said intermediate portion, the outerperiphery of said rearward portion being substantially smaller than theinterior of said barrel to form a manipulating shank, said forwardportion being normally slightly larger than said interior to form acontact portion, said contact portion having a ring of contact with theinterior of said barrel, the outer wall of said groove being at allpoints thereof a substantial distance away from said contact surface,said intermediate portion graduating in cross-section from that of saidcontact portion to that of said shank portion, all of said contact andintermediate portions being of a thickness sufficient to maintain saidcontact during shipment and storage and toprevent curling back tomaintain said contact on pushing said member forwardly.

ROBERT K. CUTTER.

